1. Field of the Invention
This invention generally relates to a marking device, and more particularly to a marking device for use in effecting marking on the surface of coil which has been rolled.
2. Description of the Prior Art
Strip coils of various qualities and diameters are produced in rolling mills. In some cases, strip coils having the same shape and size but having different qualities are produced by the same rolling line. Since they cannot be apparently distinguished from each other, it is often experienced that they are mixed with each other so as to pose a serious problem in subsequent steps.
The most common measure for avoiding this inconvenience is to put specific marks on a predetermined portion of the outer peripheral surfaces of the strip coils immediately after the delivery from the strip mill, so as to make the strip coils of different qualities distinguishable from each other.
One of the conventional methods of putting the marks is the so-called stencil method in which a stencil made of a metallic plate or a sheet of paper, from which the pattern of the mark such as letters or numerals have been punched out, is placed on the material to be marked and then paint is sprayed over the stencil. Another conventional method is the so-called stamping method, according to which a stamp carrying the desired marking pattern is pressed against the surface of the material.
These conventional marking methods are, however, inconvenient in that they necessitate a quick-drying paint or ink. The stable and continuous supply of such a quick-drying marking material is extremely difficult. Further, the first mentioned stencil method requires cleaning of the used stencils. Conventionally, this cleaning work has been made by means of a specific cleaning mechanism which is highly complicated and apt to suffer breakdowns requiring a number of maintenance operators. At the same time, the demand for automatic marking operation is increasing, because marking on the hot strip coils soon after the delivery from the strip mill is extremely severe problem and dangerous.
Under these circumstances, the present invention aims at providing an automatic marking device which can automatically perform a marking on the desired portion of the material, even when the material is still hot and even when the diameters of the materials are varied, without requiring maintenance by operators, whose presence have been necessitated in conventional marking work, and the severe problems and dangerous manual marking work under a high temperature is avoided, thereby overcoming the above stated problems of the prior art.